I advance a challenge to the coherence of Alvin Plantinga's brand of theism that focuses on Plantinga's celebrated free-will defence. This challenge draws on (but goes beyond) some ideas advanced by Wes Morriston. The central claim of my challenge is that Plantinga's free-will defence, together with certain claims that are plausible and/or to which Plantinga is committed, both requires and rules out the claim that it is possible that God is capable of engaging in moral goodness. I then critically evaluate an interesting strategy for responding to my challenge inspired by some recent work by Kevin Timpe, arguing that the response ultimately fails. The upshot of the article is that Plantinga's brand of theism is internally inconsistent; furthermore, because the claims that are in tension with the free-will defence are ones that many theists are likely to find attractive, many theists are not able to appeal to Plantinga's free-will defence in responding to the logical problem of evil.